AP24 Q2 Class 21 (Rate Laws; Initial Rate Method)

Front

What is the rate constant in a reaction?

Back

The rate constant (k) is a proportionality factor in the rate law that relates the rate of a reaction to the concentrations of the reactants. It has units that depend on the overall order of the reaction.

Front

How do you express the units of the rate constant for a second-order reaction?

Back

For a second-order reaction, the units of the rate constant are typically expressed as M^-1s^-1 (molarity inverse per second).

Front

What does it mean if a reaction is second order in a reactant?

Back

If a reaction is second order in a reactant, the rate of the reaction is proportional to the square of the concentration of that reactant.

Front

What is the effect on the reaction rate if the concentration of a second-order reactant is decreased?

Back

If the concentration of a second-order reactant is decreased, the reaction rate will decrease significantly, as the rate is proportional to the square of its concentration.

Front

How do you determine the overall order of a reaction?

Back

The overall order of a reaction is determined by summing the powers of the concentration terms in the rate law.

Front

What is the rate law for a reaction that is second order in A and first order in B?

Back

The rate law is expressed as Rate = k[A]^2[B]^1.

Front

If the concentration of A is decreased by a factor of 5.4 and B is increased by a factor of 3.6, how do you calculate the new reaction rate?

Back

Calculate the new rate by substituting the new concentrations into the rate law and comparing it to the original rate.

Front

What is the order with respect to a reactant if the rate of reaction is directly proportional to its concentration?

Back

The order with respect to that reactant is 1.

Front

How does a change in concentration of a reactant affect the rate of a reaction?

Back

A change in concentration of a reactant affects the rate of a reaction based on its order; higher order means a greater effect on the rate.

Front

What is the significance of half-order reactions?

Back

Half-order reactions indicate that the rate is proportional to the square root of the concentration of a reactant.